Since several epidemiological studies have indicated an elevated risk for certain types of cancer in both living and working environments where exposure to an extremely low-frequency electromagnetic field (ELF) occurs, public concern about ELF has been increasing because it is impossible to imagine life today without electricity. We reviewed studies on biological effects of ELF with respect to their cytological and biochemical effects, including mutagenicity, clastogenicity and carcinogenicity. The studies can be summarized as follow:
1) There is evidence that outer surface of the cell membrane is the primary locus for ELF-induced cellular alterations.
2) ELF modulate the proliferation of normal as well as transformed cells in vivo and in vitro. The magnitude of the proliferative effects depends on ELF intensity, exposure duration and other celluar factors.
3) No studies clearly demonstrate deleterious effects of ELF exposure on mammalian reproduction and development, but several suggest such effects.
4) Reported evidence does not demonstrate that the ELF acts as a cancer initiator.
However, it might act as a promotor or affect tumor progression.
Further observations and epidemiological studies of ELF must be accompanied by laboratory experiments to evaluate biological and health effects.

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Abstract Examination of the effect of noise on sleep indicated the following:
1) Views differ on habituation to noise.
2) REM sleep in all-night sleep decreases with exposure to noise. The probability of transient changes of REM sleep to other stages is low. REM sleep induction may be disturbed by noise exposure, but once it has been induced, changes to other stages or waking occur only to a small extent.
3) A transient decrease in sleep spindles is caused by noise exposure, but the number of sleep spindles for all-night sleep increases. Sleep disturbance by noise is compensated for by an increase in sleep spindles during periods of silence, possibly indicating sleep maintenance.
4) Under certain circumstances, subjective sleep is a better indicator of the effects of noise on sleep than objective sleep parameters determined by sleep polygraphy.
5) There is a linear dose-response relationship between the peak noise level and the rate of stage shift or waking. The threshold of the noise effect is about 40 dBA.

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We conducted a questionnaire survey on life styles and health status for 293 patients with Hansen's disease. They were admitted to the wards for disabled and physically able patients of Ohshima Seishoen, in Kagawa prefecture, in 1991. This institution is one of Japan's national leprosy sanatoriums. We measured patients' life satisfaction with the Delighted-Terrible Scale. In this report, the distribution of life satisfaction and its associated factors were examined for 210 (71.7%) respondents. Factors examined were length of treatment, physical health, and social aspects of life at the sanatorium. The major findings were as follows;
1. The patients aged under 60 had lower proportions of being satisfied with life than those aged 60 or older. The proportions of life satisfaction of the 40-59 age group were 17% for men and 22% for women, while for the 60 or older age groups were 33-44% for men and 41-45% for women. The proportions of life satisfaction in the 60 or older age groups were lower than those of community dwelling elderly persons.
2. We examined factors associated with life satisfaction for the respondents aged 60 or older. Dependence on activities of daily living (ADL) was associated with life satisfaction in some ADL items. Care and aid provided by the staff of the sanatorium may modify the relationship between ADL impairment and life satisfaction. For social aspects of life at the sanatorium, both having networks with family members and having resources other than family were associated with life satisfaction. Going out and positively spending their daily lives were associated with life satisfaction, too. These associations were significant for men. Similar patterns of association were observed for women, but were insignificant. This finding suggests that it is important for the health and medical care staff to pay attention to the social aspects of the life of elderly patients with Hansen's disease.

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The life style of young adults has been receiving attention with a view to its improvement to prevent coronary heart diseases (CHD) later in life. In this study, to determining the influence of different life styles on the serum phospholipids level, we carried out experimental studies on the effects a high sugar diet and physical exercise on serum phospholipid levels.
Considering the trend for young people to consume large quantities of carbonated drinks, in which most of the sugar is sucrose, we tested the effect of a high carbohydrate diet on one group of six healthy male subjects and did not find that it caused a significant increase in the serum phospholipids level.
In another group of 108 healthy young female subjects, a mild exercise regimen results in a slight, but significant decrease in the serum phospholipid level (p<0.01). The serum total cholesterol level of the group did not exhibit a significant change.

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Data on height and weight were collected at an elementary school in Fukui Prefecture from 1889 through 1934 (observation period). During the observation period, the school area, consisting of a mountainous region and a plain region, was not changed. Using these data, analysis showed that there were: (1) differences in physique between children from the mountainous region and those from the plain region, which was suggested by the school teachers during the observation period, (2) chronological changes in physique, (3) chronological changes in the features of the height velocity curve in the analysis when school children at the same school born in the 1980s were used as a control, (4) chronological changes in the balance of weight to height and (5) changes in the prevalence of obesity.
The results were as follows:
(1) during the observation period, the physiques of children in the mountainous region were consistently inferior to those in the plain region, (2) during the period, the average physique of the school children aged 12 was consistently inferior to the overall average for Japanese pupils of the same age, (3) during the observation period, the onset of the adolescent growth spurt was later by one year compared with that of current controls, (4) the ratio of weight to height stratified by 3cm intervals during the observation period was almost the same as that in current controls, (5) during the observation period, the prevalence of obesity in boys (6%) was lower than that in current controls (10%). However, the obesity prevalence in girls during the period was higher than that in the controls. However, this findings might be associated with wearing kimono during measurement.
By contrast, these differences have recently disappeared. These results suggest that there were consistent differences in physique that persisted between regions in the school area and in Japan as a whole across several eras.

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Elderly people (males 742, 65-91 years old; females 371, 65-84 years old) were asked to answer a questionnaire on health and defecation tendencies.
1. Ninety-four percent of the males and 95% of the females considered their food intake sufficient to maintain their health (no difference between sexes). As for their food intake requirements, 68% of the males and 70% of the females answered that they knew about them, while 9% of the males and 6% of the females answered that they did not (no difference between sexes).
2. Of those with regular defecation every day, there were more males (68%) than females (49%). Seventeen percent of the males and 35% of the females defecated from four to six times per week, while 14% of the males and 13% of the females did so less than three times per week, with the difference between sexes being significant (p<0.001). Both males (93%) and females (92%) tended to consider that constipation could affect their health condition. When asked about defecation, 92% of males and 83% of females answered that they should do so every day. The time for defecation was between when they arose and after breakfast for 76% of the males and 53% of the females. More females (25%) than males (8%) defecated irregularly (p<0.001, difference between sexes).
3. Of those who did not have defecate every day, the percentage for those who answered that they should do so every day was low, whereas the percentage of those who answered that regularity did not matter was high. A significant relationship between awareness and degree of defecation was found for both males and females (p<0.001 in both sexes). Those who regularly defecated every day did so in the time between when they arose and after breakfast, while those with irregular defecation did not defecate at a set time. A relationship was found between the time of defecation and the degree of defecation (p<0.001 in both sexes).

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The effects of genetic and environmental factors on bone mineral density (BMD) were investigated in 108 healthy Japanese women. Of the 108 subjects, BMD (from the second to forth lumbar vertebrae) was measured in 1992 in 103, in 1993 in 100, and in both years in 95 by dual energy X-ray absorptiometry. Vitamin D receptor (VDR) gene polymorphism in intron 8 was used as a genetic marker. Information on menstruation, health status, lifestyle, quantities of nutrient intake and frequencies of food intake was obtained by questionnaire.
The frequency of allele B (825bp), whose polymerase chain reaction (PCR) products cannot be cut with BsmI, was 0.259 and the frequency of allele b (650bp), whose PCR products can be cut with BsmI, was 0.741. The subjects in our study obeyed the HardyWeinberg law. While the frequency of allele B was 0.448 in European whites as reported by Morrison et al, it was 0.259 in our Japanese subjects, suggesting a racial difference. Z score values (average value 0, standard deviation 1) increased in the order BB, Bb and bb. This result indicates that allele B is associated with the lower BMD in Japanese, as in European whites. The BMD decrement rate increased in the order bb, Bb and BB, indicating that VDR gene polymorphism may be a regulatory factor for losing BMD. Most of lifestyle variables, calcium intake and vitamin D intake were not correlated with BMD, but the food frequency score (which was defined as values weighted in each of three food categories obtained by factor analysis) was significantly correlated with BMD. Multiple regression analysis showed significant influences of years after menopause, the food frequency score and VDR genotype on BMD. VDR genotype and years after menopause influenced the BMD decrement rate significantly in multiple regression analysis. Neither a relationship between BMD and calcium intake nor between BMD and vitamin D intake by VDR genotype was found.
These results suggest that the VDR gene is a genetic factor in BMD and the BMD decrement rate in Japanese.

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This study was conducted to compare physical strength, physique, exercise frequency and type of work of 4, 334 male and 439 female middle-aged office and outdoor forestry workers.
Both male and female outdoor workers were taller and had lower Broca's indices than their office counterparts, while the body weight of outdoor male workers was lighter and that of female outdoor workers heavier than those of male and female office workers, respectively. The number of outdoor workers not engaging in frequent exercise was found to be significantly greater than that of office workers. Male outdoor workers had significantly higher maximal oxygen uptake (cardio-respiratory endurance), grip strength (muscular strength) and standing trunk flexion (static flexibility) than the male office workers whereas the opposite was true for whole body reaction time (agility), eyes-closed one-leg balancing (static balance) and sit-ups (muscular endurance). Female outdoor workers had higher maximal oxygen uptake (cardio-respiratory endurance), grip strength (muscular strength) and standing trunk flexion (static flexibility) than the female office workers, whereas the opposite was the case for whole body reaction time (agility), eyes- closed one-leg balancing (static balance) and sit-ups (muscular endurance). All of these differences among females were significant except for maximal oxygen uptake (cardiorespiratory endurance). When indoor and outdoor workers of the same sex with similar physiques and exercise frequencies were compared male outdoor workers had higher maximal oxygen uptake (cardio-respiratory endurance) and greater standing trunk flexion (static flexibility) whereas female outdoor workers had greater grip strength (muscular strength) and standing trunk flexion (static flexibility).
From these results, it was suggested that maximal oxygen uptake (cardio-respiratory endurance) and standing trunk flexion (static flexibility) in the male workers and grip strength (muscular strength) and standing trunk flexion (static flexibility) in the female workers were related to their working situations. Both the physical strength of workers and personal characteristics must be carefully considered in order to preserve the health of both indoor and outdoor forestry workers.

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To evaluate the risk factors for diabetes mellitus, I examined 2573 people (1851 males and 722 females) who received medical checkups more than twice at a health examination center in Tokyo during the period from 1976 through 1991. Diabetic patients were excluded at the beginning. The mean follow up duration was 5.2 years. A selfregistering questionnaire was administered at the time of the health checkup. The standard of this study was the onset of diabetes mellitus or glucose intolerance (fasting blood sugar over 110mg/dl). I compared two prognosis groups (a normal group and a diabetic group) in terms of age, examination findings and prevalence of health risks (lifestyle, stress and working form). I also assessed family history of diabetes and past history including hypertension, hepercholesterolemia and hyperuricemia. After assessing each variable, I employed Cox's proportional hazards model analysis.
1) Among the subjects, 296 persons (243/1851 [13.1%] males, and 53/722 [7.3%] females) were newly diagnosed with diabetes during the observation period.
2) The diabetic group had significant differences compared to the normal group in age, BMI (Body Mass Index), FBS (fasting blood sugar), smoking, drinking, eating no breakfast, dairy intake, hypertension, hypercholesterolemia, hyperuricemia, and family history by t-test and xx² test.
3) According to proportional hazards model analysis, FBS, age, family history, hypertension, smoking and BMI were selected as significant risk factors for diabetes in males. For females, breakfast, FBS, age, drinking and hypertension were selected.
4) Diabetes seemed to be related to fixed factors such as age, or genetic factors such as famili history and FBS in males. For females, lifestyle, such as eating no breakfast and drinking habit played an important role.

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